Acetylene container filler and methods



. mawing. Eiled- Feb. 9, 1956, set. No. 564,360 4Claim5. ((31.106-120) This i vention relate t s n s for hvlt solved ac tylen whi h co a n r a e P o d d w th a porous absorbent material or filler. More particularly, the invention is, directed to an improved highly porous filler for acetylene containers together with a method of manufacturing such ;,a filler and a method of filling acetylene containers with such improved filler material.

It is well known that acetylene gas, even in very small amounts, may become violently unstable at pressures in excess of 15 p.s.i. and almost with certainty above 50 p.s.i. "'Ihis conditionissubstantially overcome by dissolving the acetylene in acetone which will dissolve as much as 6 times own weight of acetylene. .Pressures up to 300 psi. or more of dissolved gas may be obtained in this manner if the acetone container is filled with a highly porous material, the individual pores of which are minute. The material must be such however that it will not settle, shrink or disintegrate to leave voids within which acetylene gas under pressure may oollect and become unstable. In other words, in addition to high-pdrosity it must have relatively high compressive strength and dimensional stability.

" Heretoforefa large numberof materials have been proposedfor use as fillers for acetylene containers. These among others have included balsa wood, Kapoc, icieselguhr, charcoal and asbestos. Such fillers, although sound in nature, ,were limited to a porosity in theneighborhood of 75 More recently a substantially rfnonolithic filler for-acetylene cylinders been proposed, having a porosity of between 8 0% and 186%, Such a tiller coinprises the calcium silicate product obtainable by reaction between'calcium hydrate *and a material consisting 'es .sentially of 3 silica,Q-such .asusa d. form of filler, ,although good in such qualities as strength and porosity, exhibits substantial shrinkage which V it ,and its container, and'hence it h mensional stability required for complete satisfapti the intended purpose.

creates voids between its the req site di- Qt of lndhe present invention, by suitablecomhination a ;proportioi1,of ingredients,together with a predetermined h ethodpf compounding these, a highly; desirahle, dimensionally stable, high porosity, low volume and'hi'gh com pressive strength filler has been obtained, the overall porosity of which is in the neighborhood of 90% to 92%. Moreover, the invention further comprises a method for obtaining the complete filling of acetylene containers with this material. i

It is accordingly the principal object of this invention 'toprovide a filler material ofhigh porosity, low volume and substantial compressive strength capable of com- 7 pletely filling acetylene containers.

Pat n ed July 121N560 7 Still another object of this invention is to provide .a method for completely filling acetylene containers with the materials referred to in the foregoing objects, a rapid and efficient manner.

These and additional objects and advantages of the invention will become more apparent as the following description proceeds.

The preparation andcomposition of the improved acetylene container filler according to this invcntion cornprises an initial pre-treatment of charcoal and lime in the following manner. Porous charcoal, preferably screened to pass through a /2 inch mesh, is soaked underwater for at least 12 hours. In this period of the small sized pieces of charcoal absorb water to capacity.

Pulverized lime (any high calcium commercially available pulverized lime is acceptable) is hydrated with .water to obtain a slurry comprising about 20% by-weight Of the calcium oxide. g Y

Sufiicient additional water to make the entire water-tosolids ratio equal to approximately 3.8 is then placed in a mixing vessel, into which is charged fibrous asbestos. The fibrous asbestos and water are mixed until all visible air bubbles have disappeared.

The pre-soaked charcoal is then added to the asbestoswater slurry and dispersed by agitation.

At this point finely divided silicon dioxide, preferably in the form of diatomacious earth, is then added to the neous. At this point, the filler slurry may be removed from the mixer and' is ready for charging into the acetylene containers.

The following formula has been found to be preferable to obtain a porosity in the neighborhoo'd'of 92% Water to solids ratio by weight flit Silicon dioxide to lime weight ratio V 2.0 Asbestos in percent of solids by weight; Charcoal in percent of solids weight- '20 It has been found that variations may-bemade in this preferred formula, but these should not. exceed about ma tia arden 9 .sslidsPrushnp 20% as to each' iiigredient'.

Fillers having a porosity of between-:88% and 90% have been obtained bythe followinglformula:

Asbestos in percent of solids by weiglitl Other formulas which have been found to be acceptable but not to the degree of the preferred formula, principally because of lower porosities and less crushing strength are:

Silicon dioxide to lime Weight ratio 1.61 to 2.47 Asbestos in percent solids by weight.. 20 to 30 Charcoal in percent solids by weight 15 to 30 Water to solids ratio by weight 3 to 4.5

It should be noted however that any substantial increases in the water to solids ratio by weight and in the silicon dioxide to lime ratio greater than those indicated result in shrinkages in excess of those that can be compensated for by the charcoal, and this restricts their value as acetylene container fillers.

The completed filler slurry as described is placed in a 3 v hopper from which it is introduced into empty commercial acetylene container shells. the top fuse plugs of each of the shells be removed and a vacuum lineattached. The filling is preferably carried out with a vacuum maintained; at about 25 inches of mercury, When the containers are about half filled, the filling should be stopped and the cylinder vibrated or jarred for about 30 to 60 seconds. The filling is then It is preferable that one of continued until no additional slurry will flow into the containers. The containers are then again vibrated for 30 to 60 seconds, after which they are disconnected from the filling apparatus, all holes plugged, and permitted to settle for a period from 12 to 18 hours. After the filled containers have settled, overnight for example, they, are

again attached to the vibrating apparatus and jarred for another periodof 30, to 60 seconds. Filler material of the .same batch, for example from which the containers were filled the previous day,,is then introduced to fill any space remaining in the shell due to 'settling or tamping of the filler. I The top plug is then replaced and the cylinder is again vibrated for about 30 to 60 seconds It is reopened and additional filler slurry is again introduced ifnecessary. This vibrating and filling is repeated until no settling is produced on additional vibration. It has been i found generally that about three of such cycles are usually necessary to fill the containers completely. The containers are then removed from the vibrating apparatus and are in condition to be indurated.

Inorder for the proper chemical reaction to take place within the filler slurry in a reasonable length of time, heat is applied to the container while the loss of water is prevented. It has been found that this induration should be performed promptly after the final filling cycle. Since water expands in this heating process, it is necessary to provide the containers individually with hydraulic expansion heads.

A suitable oven in which the filled containers. are placed is brought to a temperature in the range of from 350 to 375 degrees Fahrenheit and is maintained within that range during the entire treatment. Induration should continue fora period of approximately 15 to 16.hours after the oven has reached 350 degrees F.

After the induration period has been completed, the filler is dried under vacuum.

After the containers have cooled, each container is then inspected to determine porosity and density, after which Commerce Commission specifications, and then filled with acetylene.

, It will be apparent to those skilled in the art that certain modifications in'the formulation of this filler material, as well as in the process of compounding and preparing it, and the process of preparing and filling the containers may be made without departing from the spirit of this invention, and such modifications are intended to be included the scope of the invention as defined by the I appended claims.

We claim:

1. Method of compounding a dimensionally stable it is charged with acetone in accordance with Interstate acetylene container filler comprising the steps of forming separate slurries of lime and fibrous asbestos with water, soaking charcoal under water until it is substantially saturated, removing the soaked charcoal from the water and mixing it with the asbestos-water slurry, admixing finely divided silica with theasbestos-water-charcoal slurry, charging the lime-water slurry into this mixture, and mixing until the whole is'homogeneous', in which the ingredients are in accordance with the following formula:

Silica to lime proportion by weight 1.61 v to 2.47 Water to solids proportion by weight 3 to 4.5 Asbestos in percent of solids by weight 20 to 30 Charcoal in percent of solids by weight 15 to 30 Silica to lime proportion by weight -Q 2.0

Asbestos in percent of solids by weight 25 Charcoal in percent of solids by weight 20 Water to solids proportion by weight 3.8

3. An acetylene container filler composition consisting essentially of charcoal and fibrous asbestos, dispersed and set in a silica-lime products, according tothe following formula: 7

Silica to lime proportion by weight 1.61 to 2.47

Water to solids proportion by weight 3 to 4.5 Asbestos in percent of solids by weight 20 to 30 Charcoal inpercent of solids by weight 15 to 30 4. An acetylene container filler composition consisting essentially of charcoal and fibrous asbestos dispersed and set in a silica-lime product, according to the following formula:

Silica to lime proportion by weight 2.0 Asbestos in percent of solids by weight 25 Charcoal in percent of solids by weight 20 Water to solids proportion by weight 3.8

with the filler material after it has been compounded,'-

5 References Cited in the file of this patent I 7 UNITED 'STATES PATENTS 835,831 Noble Nov. 13, 1906 1,204,086 Sutcliife ;Nov. 7, 19 16 2,215,891 Thompson Sept. 24, 1940 2,342,735 Hellman t ,Feb.- 29, 1944 2,422,251 OBrian June 17, 1947 2,504,579 Perl A Apr. 18, 1950 2,716,070 Seipt n Aug. 23, 1955 2,766,131 Seipt Oct. 9, 1956 

3. AN ACETYLENE CONTAINER FILLER COMPOSITION CONSISTING ESSENTIALLY OF CHARCOAL AND FIBROUS ASBESTOS DISPERSED AND SET IN A SILICA-LIME PRODUCTS, ACCORDING TO THE FOLLOWING FORMULA: 